Import error when using scan_delta

[dominikpeter]

Polars version checks

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• [X] I have confirmed this bug exists on the latest version of Polars.

Issue description

I get the following import error while using polars with the new scan_delta method:

AttributeError: module 'pyarrow' has no attribute 'fs'

Reproducible example

import polars as pl
df = pl.scan_delta("/data/nytaxi")
print(df)

Expected behavior

No import error

Installed versions

---Version info--- Polars: 0.15.4 Index type: UInt32 Platform: macOS-13.0.1-arm64-arm-64bit Python: 3.10.8 (v3.10.8:aaaf517424, Oct 11 2022, 10:14:40) [Clang 13.0.0 (clang-1300.0.29.30)] ---Optional dependencies--- pyarrow: 10.0.1 pandas: numpy: 1.23.5 fsspec: 2022.11.0 connectorx: xlsx2csv: matplotlib:

[ritchie46]

@chitralverma could you take a look at this one?

[chitralverma]

Let me check it out today.

[chitralverma]

@ritchie46 , I checked this and it seems that this is coming because I imported a sub module from the lazily loaded pyarrow, see here. I believe I will have to switch this with the below or do you recommend so other better way to lazily import sub modules also?

from pyarrow import fs as pa_fs
raw_filesystem, normalized_path = pa_fs.FileSystem.from_uri(table_uri)

Surprisingly this was not not caught in the unit tests for some reason.

[chitralverma]

@dominikpeter this issue will also happen for read_delta

[ritchie46]

er way to lazily import sub modules als

Can we import the needed pyarrow submodules within the function itself? That should prevent all issues related to lazy imports.